Key Concepts: The somatic neuromuscular junction is the site of communication between motor neurons and skeletal muscle fibres. Specialisations of the neuromuscular junction mean that activity in and release of transmitter from motor neurons produces contraction of skeletal muscle fibres rapidly and reliably.he neuromuscular junction comprises four cell types: the motor neuron, terminal Schwann cell, skeletal muscle fibre and kranocyte, with the motor neuron and muscle fibre separated by a gap called the synaptic cleft.
Causes. Headaches can be triggered by a variety of factors. The most common cause of headaches is prolonged tension or stress. These are called tension headaches or muscle-contraction headaches. Virtually everyone suffers from this at some time. Muscles in your scalp, neck, and face tighten and contract, causing spasms and pain.
Tension headaches: Also called chronic daily headaches or chronic non-progressive headaches, tension headaches are the most common type of headaches among adults and adolescents. These muscle contraction headaches cause mild to moderate pain and come and go over a prolonged period of time. Migraines: The exact causes of migraines are unknown. A popular theory is that various triggers cause abnormal brain activity, which in turn causes changes in the blood vessels in the brain. This is called the neurovascular theory.